This happens when I press the button to make a download.file() call. It's pointed at another ec2 instance hosting my api, I've got the permissions on the security groups setup to allow access from the box running the shiny server. It's also running in a Docker container.

I've tested that I can curl the api and this is accessible purely from the shiny ec2 box AND inside the shiny-server Docker container. Does anyone know why this breaks? For reference it also works running locally in a Docker container...